Devices for shaping and configuring friable material such as soil are known. For example, U.S. Pat. No. 5,980,569 (Molstad) discloses an articulated dozer blade system for performing dozing operations using an articulated blade. However, the articulated dozer blade disclosed in Molstad can only pivot about an axis which is vertical, or substantially vertical, thereby limiting the applications in which this dozer blade system can be used.
Other known devices, such as an adjustable grader-spreader bar disclosed in U.S. Pat. No. 6,308,785 (Rhoden) and a snowplow disclosed in U.S. Pat. No. 1,617,016 (Relien), include features which permit adjustment of a blade in a restricted manner. For instance, the grader-spreader bar disclosed in Rhoden has a blade frame assembly including a plurality of blade frames. The blade frames are slideably connected So that they have an adjustable overlap. Actuating devices are used to extend or retract the blade frames, resulting in adjustments to the width of the grader-spreader bar. Ground-engaging skids are attached to each side of the blade frame assembly, and the vertical position of each ground-engaging skid is adjustable. It appears that the vertical positions of the ground-engaging skids are adjustable to only a limited extent, however, so that the blade frame assembly can be positioned within a somewhat limited range of angles to the horizontal.
As another example of the prior art, the snowplow disclosed in Relien includes two blades (10, 11) and a backbone (12) having a pair of plates (14, 15). A second plate (i.e., plate 15) is positioned higher than a first plate (i.e., plate 14), and the second plate is pivotally attached to the first plate, so that the second plate can be tilted relative to the first plate. Also, the blade (11) attached to the second plate tilts with the second plate because the blade (11) is rigidly attached to the second plate. However, it appears that the snowplow disclosed in Relien permits only one of two blades to be tilted, i.e., raised at one end thereof in a vertical plane.
Because of the limits on adjustability of blades in the known devices, the known devices are not suitable for use in certain applications. For example, it is often desirable to form a relatively shallow depression, or swale, in landscaping at or around residential or commercial premises. A swale is often needed for controlling drainage, especially at or near property boundaries or between adjacent buildings. FIG. 1 shows a typical swale 20 located between buildings 22, 24. Although a variety of swale designs are used, the swale 20 is shown in FIG. 1 with a furrow or channel 26 positioned approximately centrally in the swale 20, substantially aligned with a property boundary 27. (For convenience, only portions of the foundation walls of the buildings 22, 24 are shown in FIG. 1). The swale 20 is constructed in a specified location 28 according to a predetermined swale design which is intended to result in the flow of surface groundwater over the swale 20 towards a street 29 consistent with design parameters which are in accordance with municipal or other applicable regulations. The direction of flow of surface groundwater in the typical swale 20 is away from the buildings 22, 24 and toward the street 29, as indicated by arrows A, B, and C in FIG. 1.
A cross-section of a typical swale is shown in FIG. 1A. In FIG. 1A, it is assumed that the swale as built is in accordance with the design. As can be seen in FIG. 1A, the swale surfaces 30, 32 are separated by the furrow or channel 26, which typically is substantially horizontal. Often the buildings 22, 24 are separated by a relatively small distance D. Typically, the distance separating the buildings 22, 24 is as little as approximately 6 feet, or less. As shown in FIG. 1, the swale 20 typically is located on a first property line 33. In most cases, additional swales 34, 35 are located between the houses 22, 24 and a rear property boundary 36 in order to cause surface groundwater to run off into the swale 20, as indicated by arrows F.
Because of the relatively restricted area in which the swale 20 is formed, in the prior art, the swale 20 is usually formed using manual labor, i.e., with shovels and rakes. The surfaces 30. 32 are usually positioned at approximately 1°-35° from the horizontal, as can be seen in FIG. 1A. Also, in a typical swale, the furrow or channel 26 extends from an upstream end 38 to a downstream end 40, and the grade from the downstream end 40 to the upstream end 38 generally varies between approximately 2% to approximately 16%. Known devices are not suitable for making swales in a relatively limited area and to the specifications required, due to the limitations of known devices, as described above.
There is therefore a need for a scraper with an articulated blade having independently movable left and right portions.